Subject: Ambient Noise Measurement, Creekside Park Project, Monte Rio, California

Transcription

1 22 December Laura Saunders, AICP Prunuske Chatham, Inc. 400 Morris Street, Suite G Sebastopol, CA Subject: Ambient Noise Measurement, Creekside Park Project, Monte Rio, California Dear Ms. Saunders: This letter presents the results of ambient noise measurements collected in support of the California Environmental Quality Act review of the proposed Creekside Park at the Old Monte Rio School site (Figure 1). On 7 December 2011, BASELINE Environmental Consulting (BASELINE) measured short-term noise levels at various locations near the project site. In addition, because the project would include a skateboard park, BASELINE measured the noise levels at a skateboard park in Sebastopol, California on the same day (Figure 1). A Larson Davis Laboratories Model 720 precision integrating sound level meter was used for the noise level measurements. The meter was calibrated before and after use with a Larson Davis Laboratories Cal150 acoustical calibrator to ensure the accuracy of the measurements. The equipment meets all the pertinent specifications of the American National Standard Institute for Type 1 sound level meters (ANSI SI.4). The field logs describing the monitoring locations, weather conditions, and other observations are attached. The location where the ambient noise levels were measured are shown on Figures 2 and 3. The numerical summaries of the ambient noise level measurements are provided on Table 1. Also included with the report are charts depicting the noise levels measured and field logs. The specific noise measurement locations are described in detail below. The ambient noise environment in the vicinity of the Old Monte Rio School site is generally quiet, consistent with rural areas. The area surrounding the project site is forested land with tall conifers, which serve to dampen sound with distance. The primary noise source is traffic along Main Street. We understand that noise in the area is often impacted by the activities at the parcel immediately to the north of the school property, which is being used as a staging and corporation yard for one of the contractors installing the water mains as part of the Sweetwater Springs Capital Improvement Project. At the time the noise measurements were collected, very little activity was observed at the staging and corporation yard and noise from this source did not contribute significantly to the noise measurements taken. The day the measurements were taken was sunny and clear, with temperature ranging from about 34 degrees Fareinhiet ( F) in the morning to 61 F in the afternoon. Wind conditions were

2 Laura Saunders 22 December 2011 Page 2 mostly calm, with 1 to 2 knot winds in the afternoon. Additional climate conditions are provided on the attached Field Logs. SLM-01 Noise measurements from location SLM-01 were collected at the former Monte Rio School site in front of the existing buildings. The primary source of noise was traffic on Main Street, located approximately 74 feet away (measured from the roadway centerline) and a barking dog. Nineteen vehicles pass by the site during the 15-minute measurement. The 15-minute equivalent noise levels (Leq) was measured at 57.2 A-weighted decibels (dba). The noise level may have been impacted by noise from traffic reflected off the existing buildings. SLM-02 Noise measurements from location SLM-02 were collected in the vacant lot located south of the existing buildings at the former Monte Rio School site. The primary source of noise was traffic on Main Street, located approximately 144 feet away (measured from the roadway centerline). Seventeen vehicles pass by the site during the 15-minute measurement. The 15-minute Leq was measured at 48.3 dba. SLM-03 Noise measurements from location SLM-03 were collected alongside Bohemian Highway located west of the former Monte Rio School site (Figure 2). The primary source of noise was traffic on Main Street and two vehicles that passed by on Bohemian Highway. The 15-minute Leq was measured at 58.8 dba. As shown on the attached chart, the relatively high 15-minute Leq at this location is the single truck bypass toward the end of the measurement. The noise level of 46.2 was only exceeded 8 percent of the time (1.2 minute) during the measurement period (Table 1). SLM-04 Noise measurements from location SLM-04 were alongside Middle Terrace, west of the former Monte Rio School (Figure 2). Middle Terrace is located approximately 250 higher in elevation than the former Monte Rio School. The primary source of noise was traffic on Main Street. Due to the distance from Main Street, the number of vehicles passing on Main Street could not be determined. The 15-minute Leq was measured at 40.3 dba. SLM-05 Noise measurements from location SLM-05 were collected in front of the Laguna Skate Garden, an existing skateboard park, at 700 Laguna Parkway in Sebastopol, California. The skateboard park consists of bowels, with ramps and other structures used for performing various aerial maneuvers. This measurement was taken over a 1-hour interval. The noise meter was located approximately 28 feet south of property line or 72 feet from nearest skateboard ramp and approximately 20 feet from the centerline of Laguna Parkway. The primary source of noise was fnl.docx-12/22/11

3 Laura Saunders 22 December 2011 Page 3 skaters using the park and traffic on Laguna Parkway, mainly when the skate boarders hit the wood portion of the skateboard on the concrete. The sound will the skateboards are rolling is not load relative to the other noises, due to the fact that the skateboards are equipped with urethane wheels and the concrete surfaces are smooth. During thee measurement, the number of skate boarders increased from one to twelve, with up to thirteen non-skating users. The majority of the skating activity was in the bowl closest to Laguna Parkway and the noise meter. Thirty-eight vehicles pass by the park during the 60-minute measurement. The 60-minute Leq was measured at 64.5dBA. As shown on the charts of the noise measurements, the noise from the skateboard park are more continuous than the noise from the locations in the vicinity of the Old Monte Rio School site, which are due to vehicles passing by the site. The distribution of noise at each location is also presented in Table 1, consistent with the Sonoma County noise standards for allowable exterior noise exposure for non-transportationn noise sources. The noise levels may be scaled base on distance using standard noise attenuation equations. Table1 Statistical Summary of Ambient Noise Measurements Location ID SLM-01 SLM-02 SLM-03 SLM-04 SLM-05 Notes: Measurement Duration 15 minutes 15 minutes 15 minutes 15 minutes 60 minutes Leq L L L L All measurement presented in The A-weighted decibels (dba). Leq = equivalent energy level. Lx = the noise levels that are exceeded x percent of the time during the measurement period. If you have any questions, pleasee do not hesitate to contact me at your convenience. Sincerely, James McCarty, P.E.. Senior Engineer Attachments: Figures Charts Noise Measurement Data Sheets Field Logs fnl.docx-12/22/11

4 PROJECT VICINITY MAP Figure 1 Project Site Existing Skateboard Park Monte Rio Creekside Park Project Fig1.cdr 12/22/11 B ASELIN E

5 AMBIENT NOISE MONITORING LOCATIONS Figure 2 SLM-04 Project Site SLM-01 SLM-02 SLM-03 Legend Location Monitored Monte Rio Creekside Park Project Fig2.cdr 12/22/ Feet B ASELIN E

6 AMBIENT NOISE MONITORING LOCATION Figure 3 Existing Skateboard Park Sebastopol, CA SLM-05 Legend Location Monitored Monte Rio Creekside Park Project Fig3.cdr 12/22/ Feet B ASELIN E

7 80 Sound!Level!Measurments 12/07/11 SLM" Sound!Levle!(dBA) :38:53 9:41:46 9:44:38 9:47:31 9:50:24 9:53:17 9:56:10 Time

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10 70 Sound!Level!1easurments 6789:866 SL1"9; Sound!Levle!*d+A :31:12 11:34:05 11:36:58 11:39:50 11:42:43 11:45:36 11:48:29.ime

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12 Site:Monte Rio Crkside Park Model: 720 Firmware rev: Location: SLM-01 Date: 07Dec 11 09:40:00 Overall Run Time 00:15:00.0 Start Time 07Dec 11 09:40:00 Lmax 71.0 Lmax Time 07Dec 11 09:41:05 Lmin 35.2 Lmin Time 07Dec 11 09:52:22 Peak 93.9 Peak Time 07Dec 11 09:41:23 Ln values L 2 = 68.4 L 8 = 62.6 L25 = 49.3 L50 = 44.1 L99 = 35.2 Overall Leq :15: Site:Monte Rio Crkside Park Model: 720 Firmware rev: Location: SLM-02 Date: 07Dec 11 10:13:00 Overall Run Time 00:15:00.0 Start Time 07Dec 11 10:13:00 Lmax 60.9 Lmax Time 07Dec 11 10:15:39 Lmin 34.6 Lmin Time 07Dec 11 10:13:15 Peak 80.8 Peak Time 07Dec 11 10:19:21 Ln values L 2 = 58.9 L 8 = 53.4 L25 = 45.1 L50 = 40.5 L99 = 34.6 Overall Leq :15:00.0 1

13 Site:Monte Rio Crkside Park Model: 720 Firmware rev: Location: SLM-03 Date: 07Dec 11 10:52:00 Overall Run Time 00:15:00.0 Start Time 07Dec 11 10:52:00 Lmax 84.1 Lmax Time 07Dec 11 11:06:51 Lmin 34.0 Lmin Time 07Dec 11 11:01:41 Peak Peak Time 07Dec 11 10:52:41 Unweighted Peak Uwpk Time 07Dec 11 11:06:51 L 2 = 52.9 L 8 = 46.2 L25 = 40.6 L50 = 37.2 L99 = 34.0 Overall Leq :15: Site:Monte Rio Crkside Park Model: 720 Firmware rev: Location: SLM-04 Date: 07Dec 11 11:32:00 Overall Run Time 00:15:00.0 Start Time 07Dec 11 11:32:00 Lmax 65.1 Lmax Time 07Dec 11 11:32:11 Lmin 34.3 Lmin Time 07Dec 11 11:46:39 Peak 93.6 Peak Time 07Dec 11 11:32:13 L 2 = 43.9 L 8 = 40.5 L25 = 37.7 L50 = 36.0 L99 = 34.3 Overall Leq :15:00.0 2

14 Site:Monte Rio Crkside Park Model: 720 Firmware rev: Location: SLM-05 Date: 07Dec 11 13:40:00 Overall Run Time 01:00:00.0 Start Time 07Dec 11 13:40:00 Lmax 85.7 Lmax Time 07Dec 11 13:41:38 Lmin 49.7 Lmin Time 07Dec 11 13:50:16 Peak Peak Time 07Dec 11 13:57:56 Unweighted Peak Uwpk Time 07Dec 11 13:41:27 L 2 = 73.9 L 8 = 68.3 L25 = 63.2 L50 = 60.1 L99 = 49.7 L99 = 49.7 Overall Leq :00:00.0 3

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